Heat advisory issued for coast

The National Weather Service has issued a rare heat advisory for the coast, where daytime highs are expected to rise into the low 90s through Thursday. The temperatures are being sent toward record levels by unseasonable Santa Ana winds, which have been gusting 40-50 mph across inland mountains and canyons. The high pressure that is producing the winds also is dropping the relative humidity below 15 percent in many areas, increasing the risk of wildfires countywide.

"We haven't had a May as hot as this one since in San Diego since 1896," the weather service says in an advisory. "One day this May (May 1) already cracked the four hottest May days on record. And forecast temperatures will be in striking ranging today (93); Wednesday (94) and Thursday 95).

Conditions will be worse across inland valleys and foothills, where the heat will get into the mid-90s and low 100s in many areas. Temperatures won't moderate until Friday, and even then they will be above normal.

There average monthly temperature for January, February, March and April was above normal, and May is headed the same way. There have only been eight days this year in which the daytime high at San Diego's Lindbergh Field has been below normal.